ESTROUS SYNCHRONIZATION AND THE CONTROL OF OVULATION PCattle PSmall ruminants PPigs
BASICS P Prostaglandins P Progesterone and progestogens P Gonadotropin-releasing hormone (GnRH) PEstrogens (off-label use)
Bovine Estrous Cycle
Bovine Follicular Dynamics
Plasma Progesterone, Estradiol, FSH and LH after 1 mg EB im Plasma progesterone, FSH and LH (ng/ml) 3.5 3 2.5 2 1.5 1 0.5 0 Progesterone FSH LH Estradiol 1 mg EB LH -24-12 0 6 12 18 24 30 36 42 48 Interval from estradiol benzoate treatment (hours) 50 45 40 35 30 25 20 15 10 5 0 Plasma estradiol (pg/ml)
OPPORTUNITIES IN DAIRY CATTLE P Improve reproductive efficiency by reducing or eliminating problems with estrous detection PTime the entry of heifers into the milking herd PPrerequisite for embryo transfer
OPPORTUNITIES IN BEEF CATTLE P Shortened breeding and calving seasons P More uniform calves at weaning PReduce or eliminate estrous detection PEnhance genetic improvement through AI PPrerequisite for embryo transfer
IMPORTANT REQUIREMENTS P Acceptable nutrition and health P Cattle cycling normally PRecord system PGood AI technology P Adequate facilities
PROSTAGLANDINS P Pregnant women CAUTION! NOT FOR USE BY: P People with respiratory problems
PROSTAGLANDIN PROGRAMS PDouble injection, 11 to 14 days apart < 25 mg Lutalyse or 0.5 mg Estrumate, IM P Many variations
Prostaglandin Programs
TIMING OF BREEDING PAt detected estrus PROSTAGLANDIN PROGRAMS P80 hrs (68 hrs in heifers) after the last injection of prostaglandin P72 and 96 hrs (60 and 80 hrs in heifers) after the last injection of prostaglandin
EXPECTATIONS PROSTAGLANDIN PROGRAMS P 35 to 55% pregnancy rates on synchronized estrus P>70% pregnant at 35 days
PROGESTERONE PROGRAMS MELENGESTROL ACETATE (MGA)
Progesterone Programs INTRAVAGINAL PROGESTERONE-RELEASING DEVICES P 7-day insertion period with prostaglandin on Day 6 or 7
CIDR Controlled internal drugrelease insert Approved for use in beef cattle and non-lactating dairy heifers PRID Progesteronereleasing intravaginal device No milk withdrawal
Estrous Synchronization Programs Do not precisely control the time of ovulation PConception rate is higher when females are bred at detected estrus < Estrous detection can be labour intensive < Not all females are detected in estrus PPregnancy rates may be higher with appointment insemination (e.g., with PGF programs) < Decreased conception rates < Increased AI and use of semen < However, all the females in the group are bred
OVULATION CONTROL PROGRAMS GnRH, PGF +/- CIDR or PRID
OVULATION CONTROL PROGRAMS CIDRs (or PRIDs) + Estrogens + Prostaglandins PDay 0 (am): 1 mg estradiol benzoate + 100 mg progesterone + insert CIDR PDay 7 (am): Prostaglandin + remove CIDR PDay 8 (am): 1 mg estradiol benzoate PDay 9 (pm): AI
EXPECTATIONS OVULATION CONTROL PROGRAMS P45 to 70% pregnancy rate on synchronized estrus P> 80% pregnant at 35 days
Estrous Synchronization in ewes
CIDRs (Pfizer) for small ruminants may soon be available for use in NA. Can be obtained by EDR. Not available in NA.
Medroxyprogesterone acetate Used extensively in Canada until recently Now no longer available
Equine Chorionic Gonadotropin (ecg = PMSG) Follicle-Stimulating Hormone (FSH) Activity P May enhance response during breeding season < 200-400 IU at time of device removal PEssential for success for out-of-season breeding < 400-600 IU at time of device removal
P> 60% in well-managed flocks during the breeding season P40-60% in mature ewes bred out-of-season < Lower fertility in ewe lambs
ESTROUS SYNCHRONIZATION IN SMALL RUMINANTS USING MGA (MELENGESTROL ACETATE) Feed MGA @ 0.125 mg/head q12h 9 9 9 12-16 days 9 9 300-500 IU equine chorionic gonadotropin (ecg) 8-10 hours after last feeding of MGA 9 9 24-36 hours 9 Ewes begin to exhibit estrus Timing of estrus and ovulation is probably more variable than when sponges are used but the protocol is less expensive and involves less handling. 100 µg gonadotropin-releasing hormone (GnRH) 30-36 hours after MGA (or sponge removal) will improve the synchrony of the LH surge and ovulation.
P Two injections, 9-11 days apart < ± 200-300 IU ecg with second injection PEstrus in 30-48 hrs Prostaglandins 15 mg Lutalyse or 125-150 µg Estrumate IM During Breeding season PPut rams in ~36 hrs after last injection
Control of the Estrous Cycle in Does PSimilar regimens to those used in sheep PWith progesterone devices, PGF is often given at the time of removal (longer CL life) PPGF regimen < Two doses, 11-12 days apart < During breeding season
Estrous Cycle Control in Sows P Batch weaning at ~3 weeks postpartum < Up to 90% exhibit estrus in 4-8 days < Can be enhanced by boar exposure
Estrous Cycle Control in Sows P Double injections of prostaglandins are not effective < Prostaglandins luteolytic only after Day 12 of the cycle P Altrenogest (Regumate ) progestogen < Not approved for pigs in Canada or USA
Estrous Cycle Control in Sows Post-farrowing regimen P+/-Prostaglandin just after farrowing, then PPG 600 (400 IU ecg and 200 IU hcg) or 500-750 IU ecg at weaning < Increases the incidence of fertile estrus < Estrous synchrony not good < May not be economical
Estrous Cycle Control in Sows P 750-1500 IU ecg at weaning and 500-1000 IU hcg 72-96 hrs later < Breed within 24 hrs of hcg injection < >90% conception rates < Expensive
Estrous Cycle Control in Sows Recent Developments P600 IU ecg at weaning and 2.5 mg LH 80 hrs later < Breed 36 hrs after LH < Eliminates estrous detection < Decreases doses of semen required < Does not fit in well with barn schedules
Estrous Cycle Control in Sows Possible modification of previous protocol P600 IU ecg at weaning and 2.5 mg LH 72 hrs later < Possibly use 900 IU ecg on first-litter sows < Breed 30 hrs after LH < Better fit with barn schedules
Questions?